Best GFCI to avoid nuissance trips for bath fan?

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iwire said:
The OP said the instructions indicate GFCI, that with 110.3(B) makes it required does it not?
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Yes but I am still unclear as to whether or not the fan is over a bathtub or shower. I have never seen a fan that requires gfci when not installed over a tub or shower.
 
ptonsparky said:
When my wife makes a suggestion that I do something, is it "required" or "recommended" :)

She is a 6th grade teacher, if that will influence your answer.
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Having been married for 33 years the answer is "required", the divorced guys will say "recommended". Like I tell people when I plan check, the red marks on the plans are never a suggestion.
 
cowboyjwc said:
Just saying, it's not required to be on a GFCI, so why not take it off and avoid the trips. My guess would be that it's one of those little cheapy fans.
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Actually it's a brand new Panasonic. About the best of the best you can get. It's doing it just like the cheapo Broan before it (on old wiring and a switch).
 
150909-2351 EDT

JHZR2:

When you try to switch off the current flow to an inductor you do not have a high rate of change of current, but rather on an instantaneous basis the current is the same before and after you open the switch. Rather you have a very high rate of change of voltage, and it reverses from what was applied before the switch was opened.

A shunt resistor is a waste of power to reduce the change of voltage, but it doesn't change the fact that the voltage changes instantaneously. The shunt resistor only limits the peak voltage.

A shunt capacitor, or filter is better.

I believe a rapid rate of change of voltage is capacitively coupled inside the GFCI to the SCR gate to trigger the SCR. Nothing to do with the current sensing function of the GFCI.

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